You can buy that one on ebay for less than the Novak.
I would imagine under a Gibson lid, the fake poles and real tele-bassish slugs all touch the lid. That would spread the magnetic pull all across the string area to some degree, no? A blade would maybe be more effective, but that - and the current Gibson thing - would work for picking up the strings.
So, maybe the Artec Asian things out there these days are more accurate copies, but these give you a more versatile option that doesn't chop up your Gibson, or give the visual game away like the DiMarzio Model One. I like that. My problem with the Novak is that both the concept - make it sound unlike a Gibson - and the sound clips don't really do that much for me, or sound that unlike a DiMarzio which won't set you back that much money. And two points off for claiming on the website the original mudbucker isn't humbucking. If they were referring to a 53-58 mudbucker, cool, but that isn't what they were replacing.
My ears heard the sack-less Epi mudbucker as sounding Gibson-y. I don't dislike the DiMarzio Model one. The Model G is a Model One with the coils tighter together, and no epoxy blob. It can fit in and sounds a bit different. Shadow made a bass humbucker 20 years ago that was built like a regular guitar humbucker, but bigger physically. That sounded nice too. I haven't seen one in a few years.